This thesis addressed the problem of recognizing 3-D objects, using shape information extracted from range images, and parameterized volumetric models. The domains of the geometric shapes explored is that of complex curved objects with articulated parts, and a great deal of similarity between some of the parts. These objects are exemplified by animal shapes, however the general characteristics and complexity of these shapes are present in a wide range of other natural and man-made objects. In model-based object recognition three main issues constrain the design of a complete solution: representation, feature extraction, and interpretation. this thesis develops an integrated approach that addresses these three issues in the context of the above mentioned domain of objects. For representation I propose a composite description using globally deformable superquadratics and a set of volumetric primitives called geons: this description is shown to have representational and discriminative properties suitable for recognition. Feature extraction comprises a segmentation process which develops a method to extract a parts-based description of the objects as assemblies of defoemable superquadratics. Discontinuity points detected from the images are linked using 'active contour' minimization technique, and deformable superquadratic models are fitted to the resulting regions afterwards. Interpretation is split into three components: classification of parts, matching, and pose estimation. A Radical Basis Function [RBF] classifier algoritm is presented in order to classify the superquadratics shapes derived from the segmentation into one of twelve geon classes. The matching component is decomposed into two stages: first, an indexing scheme which makes effective use of the output of the [RBF] classifier in order to direct the search to the models which contain the parts identified. this makes the search more efficient, and with a model library that is organised in a meaningful and robust way, permits growth without compromising performance. Second, a method is proposed where the hypotheses picked from the index are searched using an Interpretation Tree algorithm combined with a quality measure to evaluate the bindings and the final valid hypotheses based on Possibility Theory, or Theory of Fuzzy Sets. The valid hypotheses ranked by the matching process are then passed to the pose estimation module. This module uses a Kalman Filter technique that includes the constraints on the articulations as perfect measurements, and as such provides a robust and generic way to estimate pose in object domains such as the one approached here. These techniques are then combined to produce an integrated approach to the object recognition task. The thesis develops such an integrated approach, and evaluates its perfomance inthe sample domain. Future extensions of each technique and the overall integration strategy are discussed.

Background. Several methods have been used to simulate soft body deformation, such as mass-spring systems and position-based dynamics. This has been done using tetrahedral mesh models for preservation of shape and volume. In real-time applications however, there is a limitation to how high resolution the model can be, creating the need for optimizations. Objectives. To achieve better performance for high resolution models, tetrahedral deformation is used, making it possible for the tetrahedral mesh and triangle mesh to use different resolutions. In combination with this, the GPU is used to execute the simulation in parallel, improving performance further. Methods. For evaluation of performance and accuracy, an implementation was created to simulate soft body deformation using extended position-based dynamics and the Vulkan graphics API, with the option to use tetrahedral deformation. By experimentation, comparisons are made between using different resolutions on the tetrahedral mesh to the full resolution in terms of performance and accuracy. Results. The results show that performance and accuracy are altered when using tetrahedral deformation on lower resolution tetrahedral mesh. The performance is improved based on the decrease in workload, such as with higher base resolution models or multiple soft bodies. The accuracy is however not correlated to the reduction of resolution, but instead dependant on the rest shape of the model used. Conclusions. The implementation created demonstrates a new optimization that can be used to simulate soft body deformation in parallel on the GPU, with a smaller change in accuracy. Improvements exist in areas of usability, features and other optimizations that can be further explored in future research.

O trabalho objetivou fazer a caracterização da estrutura horizontal por meio do índice de valor de importância (IVI) e como objetivos específicos de determinar o volume de madeira de dez espécies com maior domínio em um fragmento de Cerrado sensu stricto no município de Gurupi-TO, através da utilização de equação volumétricas e do fator de forma. Os dados foram provenientes de cubagem relativa de árvores em pé e seus volumes obtidos pela equação de Hohenadl (10 seções). Foram coletados diâmetros de 323 árvores-amostras em 5 classes diamétricas, com intervalos de 2cm. Foram selecionados 10 modelos volumétricos, sendo estes denominados: Ogaya, Stoate, Rezende et al. (2006), Scolforo e Silva (1993), Meyer, Spurr (Logaritmo), Kopezky-Gehrhardt, Hohenadl-Krenn, Brennac e Schumacher-Hall, para o ajuste dos dados. Para a avaliação adotou-se critérios estatísticos: R² aj, Syx, além da análise gráfica da distribuição dos resíduos. Para as 10 espécies obteve-se uma produtividade média em termos de área basal de 7,05 m² ha-1 e volumes estimados pela equação e pelo fator de forma, valores de 25,25 m3 ha-1 e 26,87 m3 ha-1, respectivamente. O fator de forma médio foi de 0,67 para as 10 espécies avaliadas. Conclui-se que fator de forma pode ser utilizado para as estimativas de volume em áreas onde predominam uma dominância de espécies ou grupos de espécies com características semelhantes ao deste estudo, especialmente em áreas de Cerrado sensu stricto em alternativa as equações volumétricas e que o modelo de Meyer apresentou o melhor desempenho para estimativa do volume em 10 espécies em uma área de Cerrado sensu stricto. / The work aimed to make the horizontal structure characterization through the importance value index (IVI) and specific objectives to determine the volume of ten wood species with larger field in a Cerrado sensu stricto fragment in the municipality Gurupi-TO, through the use of volumetric and equation of the form factor. The data was from standing trees relative space and their volumes obtained by the Hohenadl equation (10 sections). 323 diameters were collected trees-samples in 5 diamétricas classes, with intervals of 2 cm. 10 volumetric models were selected, these being called: Ogaya, Stoate, Raj et al. (2006), Scolforo and Silva (1993), Meyer, Spurr (Logarithm) Kopezky-Gehrhardt, Hohenadl-Krenn, Brennac and Schumacher-Hall, for the adjustment of the data. For evaluating statistical criteria adopted: R ² aj, Syx, in addition to the graphical analysis of the distribution of waste. For the 10 species obtained an average productivity in terms of basal area of 7.05 m ² ha-1 and volumes estimated by equation and by form factor, 25.25 values m3 ha-1 and 26.87 m3 ha-1, respectively. The average form factor was 0.67 for the 10 species evaluated. It is concluded that form factor can be used for the volume estimates in areas where a dominance of species or groups of species with similar characteristics to this study, especially in areas of Cerrado sensu stricto as an alternative the volumetric and equations that model of Meyer presented the best performance for volume estimation in 10 species in an area of Cerrado sensu stricto.

Submitted by (ana.araujo@ufrpe.br) on 2016-08-03T15:37:53Z No. of bitstreams: 1 Luiz Medeiros de Araujo Lima Filho.pdf: 6714156 bytes, checksum: 8537b197237b8261b5b264ad769ab466 (MD5) / Made available in DSpace on 2016-08-03T15:37:53Z (GMT). No. of bitstreams: 1 Luiz Medeiros de Araujo Lima Filho.pdf: 6714156 bytes, checksum: 8537b197237b8261b5b264ad769ab466 (MD5) Previous issue date: 2012-10-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Knowledge of growth and production present and future of trees in forest stands is a key element in sustainable forest management. It is intended in this thesis to estimate the frequency distribution by diameter class, estimate and compare volumetric equations via symmetric nonlinear models as well, propose to compare models and adjust volume growth via symmetrical nonlinear models in Eucalyptus spp. clones in the region of the Araripe - PE. The experiment was conducted at the Experimental Station of the Agricultural Research Company of Pernambuco (IPA), located in the municipality of Araripina - PE. This experiment consists of 15 clones of Eucalyptus spp., species and hybrids resulting from natural crossing and controlled pollination. The database is composed of all the survival trees of the experiment, corresponding to 1189 trees, divided into three groups. To estimate the diameter distributions were adopted probability distributions Normal, with three parameters Weibull, Log-normal and Gamma. The next step was to fit of the model of Schumacher and Hall and Spurr model associated the following symmetric distributions: Normal, Student t, Exponential Power and Logistics II. The volume growth models in this thesis were adjusted with symmetric distributions associated with them. In the estimation of the diameter distributions, the results were similar in the three groups, with emphasis on the Log-normal distribution. This distribution was the most appropriate for most of the period. Analyzing the volumetric equations, it was found that the model was Schumacher and Hall the most suitable, when associated with the Student t distribution with three degrees .of freedom and Exponential Power (t = 0,8) respectively to groups I and II. In group III, the model Spurr associated with Exponential Power (t = 0,8) distribution had the best performance. Comparing the volume growth models, it was observed that the proposed models best fits obtained in this thesis, when the distributions associated with the Student t with three degrees of freedom and Exponential Power (t = 0,8), respectively, in groups I and III. In group II, the Chapman-Richards model associated with Student t distribution with three degrees of freedom had the best performance. / O conhecimento do crescimento e da produção presente e futura de árvores em povoamentos florestais é elemento fundamental no manejo florestal sustentável. Desta forma, pretende-se nesta tese estimar a distribuição de frequência por classe diamétrica, estimar e comparar equações volumétricas via modelos simétricos não lineares, bem como, propor, ajustar e comparar modelos de crescimento em volume via modelos simétricos não lineares em clones de Eucalyptus spp. na região da Chapada do Araripe - PE. O experimento foi desenvolvido na Estação Experimental da Empresa Pernambucana de Pesquisa Agropecuária (IPA), localizada no município de Araripina - PE. Esse experimento é composto por 15 clones de Eucalyptus spp., resultantes de espécies e híbridos de cruzamento natural e polinização controlada. A base de dados foi composta por todas as árvores sobreviventes do experimento, que corresponde a 1189 árvores, dividida em três grupos. Para estimar as distribuições diamétricas foram adotadas as distribuições de probabilidade Normal, Weibull com três parâmetros, Log-normal e Gama. Em seguida, procedeu-se com os ajustes dos modelos volumétricos de Schumacher e Hall e de Spurr associados as seguintes distribuições simétricos: Normal, t de Student, Exponencial Potência e Logística II. Posteriormente, os modelos de crescimento em volume propostos nesta tese foram ajustados associados às mesmas distribuições simétricas. Na estimativa das distribuições diamétricas, os resultados foram similares nos três grupos, com destaque para a distribuição Log-normal. Essa distribuição foi a mais significativa na maior parte do período avaliado. Analisando as equações volumétricas, observou-se que o modelo de Schumacher e Hall obteve o melhor desempenho, quando associado as distribuições t de Student com três graus de liberdade e Exponencial Potência (t = 0,8), respectivamente, para os grupos I e II. No grupo III, o modelo de Spurr associado a distribuição Exponencial Potência (t = 0,8) obteve o melhor desempenho. Comparando os modelos de crescimento em volume, observou-se que os modelos propostos nesta tese obtiveram melhores ajustes, quando associados as distribuições t de Student com três graus de liberdade e Exponencial Potência (t = 0,8), respectivamente, nos grupos I e III. No grupo II, o modelo de Chapman-Richards associado a distribuição t de Student com três graus de liberdade obteve o melhor desempenho.

Cette thèse s’intéresse à la synthétisation de paysages naturels, et plus particulièrement, à leur portion céleste. L’aspect du ciel est gouverné par de nombreux phénomènes atmosphériques parmi lesquels les nuages jouent un rôle prépondérant car ils sont fréquemment présents et couvrent de grandes étendues. Même sans considérer directement le ciel, la densité des nuages leur permet de modifier intensément l’illumination globale d’un paysage. Les travaux de cette thèse se concentrent donc principalement sur l’édition, la modélisation et l’animation d’étendues nuageuses aux dimensions d’un paysage. Comme la simulation thermodynamique de la formation des nuages est difficilement contrôlable et que les détails du volume simulés sont rapidement limités, nous proposons plutôt une méthode par génération procédurale. Nous érigeons un modèle léger de paysage nuageux sous forme d’une hiérarchie de fonctions. Les détails les plus fins sont obtenus par composition de bruits procéduraux et reproduisent les formes de différents genres de nuages. La présence nuageuse à grande échelle est quant à elle décrite à haut niveau et à différents instants par des cartes dessinées par l’utilisateur. Ces cartes discrètes sont transformées en primitives implicites statiques ensuite interpolées par métamorphose en prenant en compte le relief et les vents pour produire des trajectoires cohérentes. Le champ implicite obtenu par mélange des primitives interpolantes constitue le champ spatiotemporel de densité nuageuse. Des images sont finalement synthétisées par rendu du milieu participatif atmosphérique selon notre propre implémentation exécutée en parallèle sur carte graphique / This thesis focusses on the synthetization of natural landscapes, and more particularly on their celestial part. The aspect of the sky is governed by plenty of atmospheric phenomena, among which clouds play a major role for they are recurrent and widespread. Even without directly considering the sky, the density of the clouds allows them to intensely modify the global illumination of a landscape. The work of this thesis thus focuses mainly on the editing, modelling and animation of cloud areas of landscape dimensions.Because the thermodynamic simulation of cloud formation is hard to control and its maximum resolution quickly limits the details of the simulated volume, we propose instead a procedural generation method. We build a lightweight cloudscape model as a hierarchy of functions. The finest details are obtained by composing procedural noises and reproduce the specific shapes of different kinds of clouds. The large-scale cloud presence is described at a high level and at different times by maps drawn by the user. These discrete maps are transformed into implicit static primitives and then interpolated by morphing, accounting for relief and winds in order to produce coherent trajectories. The implicit field obtained by mixing the interpolating primitives represents the spatiotemporal field of cloud density. Images are finally synthesized by rendering of the atmospheric participative medium according to our own implementation, executed in parallel on a graphic card